Apparatus for tensioned cold rolling in reversible mills



Sept. 22, 1936. E. B. HUDSON 2,054,819

APPARATUS FOR TENSIONED COLD ROLLING IN REVERSIBLE MILLS Filed May 10, 1954 .lN VENT OR.

N. ATTORNEYS.

Patented Sept. 22, 1936 PATENT OFFICE APPARATUS FOR TENSIONED COLD ROLL- ING IN REVERSIBLE MILLS Edwin B. Hudson, Middletown, Ohio, assignor to The American Rolling Mill Company, Middletown, Ohio, a corporation of Ohio Application May 10, 1934, Serial No. 124,931

8 Claims.

It has hitherto been attempted to roll strip material of sheet width in reversible mills, usually of the four-high type, and also to apply considerable tension to the strip as it is being so rolled. Single stand mills of this general type have certain disadvantages in operation, however. They are limited in the production of tonnage, due primarily to conditions imposed by the hot mills upon which the strip sheets are made. These hot mills are able to turn out only relatively short coils, the usual length being about three hundred to four hundred feet. These short coils make it necessary to operate at relatively slow speeds, at least on the early passes. other disadvantage of short coils is that the length of the strip sheet used up in fastening the strip sheet to the drums on either side of the mill amounts to a very considerable length of metal as compared with the length of the coils employed. This metal cannot be rolled because it cannot be caused to enter the mill; and as a consequence, it has to be either discarded or made into some other product. These unrolled ends, together with strip degraded by cobbles and breakage, amount usually to around three hundred pounds per ton of metal, and in the ordinary plant may represent as much as $50,000 loss per year.

The general objects of my invention are, to provide rolling apparatus of the reversible mill type capable of rolling thin metalgauge strips in larger quantities than is possible with the type of equipment hitherto in use; to provide a mill and associated apparatus which is economical in first cost and very economical in operating cost; to provide for the rolling of coils of metal which greatly exceed the length. of the strip sheets furnished by the hot mill, and usually will be from ten to fifteen times as long, whereby the length of the coils furnished by the hot mill is not determinative of the length of the coils supplied to the cold mill; to provide means to insure the rolling of the greatest amountof strip with the minimum of scrap loss; to provide a way of eliminating unrolled portions .of the strip or strip sheet; to provide means for permitting a greater surface speed of rolling; and to provide a system in which the portions of the strip being rolled may be maintained continuously under a constant gauge reduction, and so as to maintain predetermined constant tension so as to insure.

and mechanism for rolling endless .lengths of metal in reversible mills", Serial No. 741,133, filed August 23, 1934, I have set forth a method of rolling strips of endless lengths involving the segregation of a given portion of an endless strip 5 for rolling purposes, and the rolling of this strip backwardly and forwardly through a reversible mill or series of mills until it is reduced to the desired gauge. When this has been accomplished the rolled portion of the strip is paid out, and an 10 additional portion is segregated for rolling purposes. =In this way the end scrap loss is eliminated. In my present case I do not keep the strip in an endless length during the rolling operation, but segregate a portion of it by severing that portion from the endless supply. In this way I do away with the necessity of apparatus for taking'up unsevered lengths of the strip on either side of the mill, and can thereby reduce the quantity of apparatus necessary and the overall space taken up by the apparatus in general. But in this case I have also provided means and a method whereby the production of unrolled ends of the strip is eliminated, and scrap loss from this source is avoided. I

Essentially in the practice of my invention, I take the strip sheets produced on the hot mill and weld successive strip sheets end to end until "I have accumulated a' large quantity of stock for rolling. This large quantity of stock, usually in the form of a coil of metal say of 25,000 lbs. in weight or more, isthen passed through a reversible mill or series of mills backwardly and forwardly until it is reduced to gauge. on either side of the mill I provide means for maintaining in the strip constantly a predetermined tension of constant amount, and I also provide tensioning means and means in thenature of coiling meansat either side of the mill or mills, to take up the strip during rolling as it isfed through the mills. In thisway I produce at each operation of the mill a length of strip weighing say, 25,000 lbs. or more, which has been completely reduced to gauge excepting for a relatively short portion at one end thereof as dist nguished from unrolled portions at both ends of t e strip in previous attempts to roll strip sheets on the reversible mill. Moreover, upon the succeeding operation of iny mill this unrolled portion at the trailing end of the preceding strip is now rolled to gauge, so that I do away with scrap loss arising from this source. Y

Moreover, by the provision of large rolls of stock for rolling, I am able toincrease the speed of the rolling operation. It has been found by exnecessarily, an electrical butt-welder.

periment that high surface speeds during rolling have advantages other than higher tonnage. Lower mill screw pressures may be used, and the strip work hardens at a slower rate, due to the temperature developed in the strip by cold working at a very rapid rate. The strip has less time to radiate its developed heat between the various passes, or between the pass and the coilingpoint, so that the strip enters the following pass or passes at a'higher temperature. This aids in its reduction.

These various objects of my invention, and

others which will be set forth hereinafter, or

sheet coil 2 may be supported and unwound, the pinch rolls 3 and knee roll 4 serving to decoil and somewhat straighten the metal; The decoiler is operated by a prime mover and suitable drive indicated generally at 5. to a shear 6, where the leading end thereof may The strip next passes be squared to facilitate the formation of a buttweld joint to the trailing end of a preceding strip. A welder is indicated generally at l, which may be of any suitable type, preferably, though not A flash cutter indicated at 8, the purpose of which is to remove from the weld any portions of the Prime mover r I I".

. smooth drum l9 with. means for will'hereinafter be described, and a flexible outer metal which extend up above the general plane of the surfaces of the strip sheet. Pinch rolls 9 serve either to hold or to pay out the metal.

By the juncture of succeeding coils=to a su ply of strip sheet, rolling material is accumui ted upon a reel I0, which may be driven by a suitable Ordinarily in the practice of my invention, I accumulate upon the reel I 0 a coil of metal weighing 25,000 lbs. or more, and consisting of one large .coil say of 3500 to 4000 feet in length. This coil I have indicated at I2.

I have shown pinch rolls l3 lying beyond the coiler l0, and beyond this a welding device l4, pinch rolls l5, and a flash cutter Hi. In this group of apparatus a shear may be included, if desired. Beyond the flash cutter I6 I have shown a supporting roll I! and a table l8.

I have next shown a type of coiling device which I refer to as a friction coiler. Thisv comprises a driving it, which sheath member of chain form comprising rollers and interconnecting links 2|. This outer sheath is-supported at one end by a pivoted member 22, and is caught at its other end by cables 23 which pass over drums 24 on a shaft 25. This shaft 'bearsat its end another drum 28, to which a cable Z'Iis attached. A weight 28 is fastened on the end of the cable. The operation of this weight is to tighten up on the sheath member which, since its other end is fastened to the pivoted member 22, is able to conform to the surface of coils of varying size upon the drum I9.

I have shown a deflector or guide member 38, the function of which is to guide the end of a strip into the friction coiler. The strip may be view thereof, withv thought of as coming into the coiler from the right in Figure 2., When the coiler is empty, the :sheath member comprising elements 20 and 2| encircles the drum l9, and the action of the deflector 36 is to lead into this cradle the end of the sheet, so as to wrap it about the drum l9. Thereafter the sheath functions to keep thestrip tightly wrapped about the drum, irrespective of the size of the coiler. may be actuated in any way desired; either manually or automatically, as by means of a fluid pressure cylinder with suitable controls.

The next piece of apparatus is a continuous The deflector member 36 l pulling device comprising pinch rolls 29 and 30,

and a series of rolls 3| which are arranged in staggered relationship, and about which the strip passes sinuously. The purpose of the pinch rolls 29 and 30 is to keep the strip tightly in contact with theJrolls 3|, which are rolled. through a suitable gearing indicated generally at 32 and 33 from a prime mover 34. These rolls therefore exert a tension upon the strip as it passes through them, as will be readily understood, and this device, which I shall hereinafter refer to as a continuous puller, is of a type set forth in .my co-pending application Serial No. 668,100,

filed April 26, 1933.

I have shown the shaft I 9a of the drum of the friction coiler driven by a belt 35 from a pulley driven by the prime mover 34. This particular drive is, of course, not essential but I have indicated it as setting forth a type of slip drive to compensate for changes in surface speed due to the growth or diminishing of a coil of metalv in the friction coiler, as will be well understood.

The last roll 31 of the continuous pulling device, serves also as one of the knee rolls of a static tension applying device. The other knee roll is indicated at 38, and a pull roll 39 is also shown mounted on a bearing member 40 which operates in ways 4| in the framework supporting the aforesaid rolls. In the particular embodiment illustrated, the strip indicated at 42 is shown passing, under theknee rolls 31 and 38, and over the pull roll 39, although this particular method of threading is not a limitation upon my invention. The roll 39 is urged upwardlyby the action of a hy-'- draulic cylinder indicated at 43, connected by a conduit 44 to a hydraulic accumulator 45. This accumulator can be loaded in such a way as to cause the pull roll 39 to exert a continuous force upon the strip 42. If, due to sporadic changes in rolling conditions, the strip 42 becomes.shortened or elongated inthat portion of it which extends between the continuous miller and the mill next to be described, the tensionin the strip will nevertheless not change, but the roll 39 will move upwardly or downwg rdl with or against the force of the hydraulic cylinder, to allow for these changes inlength. The movements of the roll 39 occurring in this way are utilized, when they extend beyond a middle zone of no control, to vary the speed of other dynamic instrumentalities in the train either preceding or succeeding it. .Thus, the device comprising rolls 31, 38, and 39 (which I shall hereinafter refer to as a static tensiorf takeup device) may be caused to control the speed either of the continuous puller hereinabove described, or of the mill hereinafterv to be described. The operation. of the static tension take-up device and the general features which go to make up its corfstruction, are set'forth' more in detail in my co-pending application entitled Rolling under tension, referred to hereinabove.

The strip 42 next is carried to a mill shown in working rolls 41.

the drawing and comprising housings l6 and working rolls 41. While this is not a limitation upon my invention, yet, for the purpose of making drastic cold rolling reductions, and more particularly for rolling strip sheets into thin gauge metal, such as tin plate, I prefer ,to use small The small working rolls, of course, are backed up by larger rolls 48, and the type of mill I have shown in my drawing is known as the four-high mill. The mill will be driven in any suitable manner, and in this type of mechani-- cal organization will be of the reversible type, normally, since.in,reducing metal to thin gauges, more than one pass through the rolls is desired. Normally the mill and the rolling operations will be so adjusted as to reduce the strip sheet to finished gauge in three or five passes. The number of passes will preferably be uneven, since it will be desired to deliver the finished pieces on the side opposite to the side of its entry into the mill. I have shown but one rolling mill; but it will be clear that more than one or a train of cold mills, may be employed if desired.

Upon leaving the mill the strip goes through another static tension take-up device comprising appropriate framework, knee rolls 49, and a pull roll 50, preferably actuated in the same way as heretofore described, by a-hydraulic cylinder 5| connected by a conduit 52 to an accumulator 53. I have shown in my drawing a pump. feeding both accumulators. It will be understood that I may use other means than a hydraulic cylinder for actuating the pull rolls of my static tension take-. up devices, such as a system of cables and weights, for example.

While, beyond the static tension take-up device just referred to, it would be practicable to place another continuous puller and a reeling device or other take-up means, to which'tensioning power does not have to be applied, and while this is within the scope of my invention, yet I have not found it necessary to do this, and prefer for economys sake to employ a type of tight coiler. Inasmuch as the operation of my mill is to be as eflicient from point of time as possible, I provide a tight coiler device of a type permitting an already formed coil to be unwound and removed while a new coil is being wound up under tension. Consequently, I have shown a base 55 upon which I pivot, by means of a shaft 56, a pair of arms 51 and 58 forming a cradle for two tight coiling mechanisms indicated respectively at 59 and 60. This cradle can be swung about by means'of a small motor BI, and through a suitable drive 62,

so as to position the driving head 63 of either of the tight coiling mechanisms in alignment with a clutch member 64. In Figure 1 a tight coiler spindle 59 is shown as connected by the clutch 64 to a shaft 65 which is driven by a motor 66 through suitable gears 61. Ordinarily in the operation of my system, the first static tension take-up device will be caused to control the speed of the mill motor, and the second static tension take up device will be caused to control the speed of thetight coiler; the speed of the continuous puller shown in Figures 1 and 2 being the fundamental basis for the controlled speeds of the other dynamic instrumentalities in the train. The second static tension take-up device therefore acts to maintain constant tension in spite of sporadic variations in the operation of the final'tight coiler. Since the' final tight coiler is controlled in speed by the static tension take-up device, the power applied to the tight coiler is caused to vary in accordance with the diameter of the coil of metal formed on the tight coiler spindle. I'have shown a coil 68 being wound up on the tight coiler spindle 59 while a coil 69 is being removed from the spindle 60 and coiled upon a spindle mechanism as at 10, to form a package of the metalsuitable for-shipment or storage. It will be understood, of course, that instead of forming a coil as at 10, the reduced strip may be cut apart into sheets by a suitable shear.

In the operation of my device, coils of metal from the hot mills are welded together end to end to form a large coil l2. At the start of all operations of the metal, an end of this coil is led through the continuous puller and the static tension device, then through the mill, through the next static tension device, and to the tight coiler to which the end thereof is afiixed. The mechanism is started in operation and the strip rolled to very near its trailing end, leaving always 'suflicient of the metal to be caught by the pinch rolls 29 and 30. The deflector 36 is next dropped and the mill and other associated instrumentalities reversed, whereupon the strip moves in nately either upon the final tight coiler or upon the initial friction coiler.

When the piece has been reduced to gauge, it being assumed that the piece is finished by a for- In this way the piece is rolled backwardly ward pass in the mills, its trailing end will extend sufiiciently to be caughtwith the pinch rolls 29 and 30, and the greater portion of the length of the strip will be wound upon the tight coiler 59 to form the coil 68. The strip will be clamped ahead of this coil and cut off, whereupon the cradle formed by the arms 51 and 58 will be rotated to bring the now empty tight coiler spindle 60 into position to be operatively connected with the driving shaft 65 by the clutch 64, and to bring the coil 68 inv a position to be decoiled. In this first operation there will be an initial length of the leading end of the strip forming the coil 68, which will not be rolled. This can be cut off as scrap, or used for some other purpose; but end loss will not occur againin the operation of this system for reasons which will hereinafter be described. That is 'to say, after the rolling of the initial batch of material, no-more end scrap loss will be encountered until it is necessary, for some reason or other, to dethread the material or to take the system down for repairs or replacements.

The next step will be to weld the to the leading end ofa new supply of rolling material which, it will be understood, has been accumulated in the meantime upon the reel I2;

, trailing end of the strip extending through the rolls 29 and 30,

This welding is done by means of the device [4.

that when the next supply of rolled stock is 7 taken from the mill as aforesaid, all parts of it will be uniformly down to gauge. The system 01' operations hereinabove described is repeated for each batch of material. It will be observed that in my mechanism three distinct operations are 5 going on at the same time: first, the formation of a supply of rolling material of great length and weight, formed by the welding together in the end of a plurality of strip sheets from the hot mills; second, the forward and reverse rolling of -a preceding supply already so formed; and third, the decoiling or cutting apart into sheets of an already rolled supply of material.

During the course of the rolling, the continuous puller upon one side of the mill and the tight coiler upon the other side of the mill, act to exert tension upon the strip, which tension is of material assistance in rolling. By the use of tension I do not primarily refer to such minor amounts of tension as are useful in feeding the mill or mills and in reducing camber. Rather I prefer to use heavy tensions such as facilitate the reduction of the metal by the cold mills. The tension produced by the continuous puller and the tight coiler is maintained at a constant value by the static tension take-up devices, which act continuously to make the tension constant in spite of variations in the length of the strip between the several dynamic instrumentalities, and to control the speeds of these instrumentalities if variations greater than normal or accumulative variations occur. It will be clear that thecontinuous puller and the tight coiler act on succeeding passes respectively as brakes and as pvllers, and vice versa.

Modifications may be made in my invention without departing from the spirit thereof.

Having thus described my invention? what I claim asnew and desire to secure by Letters Patent, is:

1. In a rolling apparatus, the combination of a decoiler, a welder, means for accumulating large coils formed by welding, a welder, a coiler, a mill,

and a coiler, in the order named, and means intermediate at least said first coiler and'said mill for producing tension on the strip being rolled.

2. In a rolling apparatus, the combination of a decoiler, a welder, means for accumulating large coils formed by welding, a welder, a coiler, a mill,

, and a coiler, in the order named, means intermediate at least said first coiler and said mill for producing tension on the strip being rolled, and means on either side of said mill for maintaining the tension of the strip constantly at predetermined values.

3. In a tension rolling apparatus for metal strip,

-the combination in the order named of'a coiling device acting as an accumulator for strip, a continuous puller for exerting tension on the strip,

a mill, and a coiling device adapted to exert tension on the strip.

4. In a tension rolling apparatus for metal strip, the combination of. a non-tensioning coiler, a continuous puller for exerting tension' on the strip, a mill, a second continuous puller, and a coiler, in the order named.

5. In a tension rolling apparatus for metal strip, the combination of a non-tensioning coiler, a continuous puller for exerting tension on the strip, a static tension take-up device for maintaining said tension constant in spite of the variations of elongation, a mill for elongating the strip, a second static tension take-up device, and a tight coiler for exerting tension on the strip, in the order named. I 1

6. In a tension rolling apparatus, the combination of a means for holding a large supply of strip rolling material in coiled form, welding means for joining said supply to the end of a previously rolled supply, a take-up coiler for said supply, a continuous puller for exerting tension thereon, a mill for elongating said supply and a tight coiler for exerting tension thereon, in the order named.

nation of a means for holding a large supply of strip rolling material in coiled form, welding means for Joining said supply to the end of a previously rolled supply, a take-up coiler for holding said joined supply, a continuous puller for exerting tension thereon, a mill for elongating said supply, and a tight coiler for exerting tension thereon, in the order named, said tight coiler comprising interspaced tight coiler spindles, and means for operatively connecting said spindles to a drive alternatively so that one of said spindles may act as a tight coiler, while a rolled supply of material is being removed from said other spindle.

8. In a tension rolling apparatus, the combination of a decoilerfor coils of strip material, a welder for joining the ends of strips, means for accumulating large coils of strip formed by the welding of strips together, a second welder for joining an end of said large coils to an end of. a supply of strip previously rolled, a coiler acting as an accumulator for a large supply of strip rolling material constituting such large coils, a mill for elongating said supply and a coiler located on the opposite side of said mill, in the order named.

EDWIN B. HUDSON. 

